Fan



C. R. PATON Feb. 25, 1936.

FAN

Filed Feb.l 1, 1955 Eby-:ER F5 TUN.

Patented Feb. 25, 1936 PATENT OFFICE FAN Clyde R. Paton, Birmingham, Mich., assignor to Packard Motor Car Company, Detroit, Mich., a corporation of Michigan Application February I1, 1933, Serial No. 654,609

3 Claims. (Cl. 17o-161) 'This invention relates to fans and more particularly to fans employed with cooling systems for the power plant o! motor vehicles.

As the i'an for engine cooling systems is driven by the engine, its speed of rotation varies in accordance with the speed of the engine. Noise resulting from the fan operation also varies in accordance with the engine speed and, at higher speeds, is quite objectionable no'w that other parts of the vehicle are `being quieted. The volume of air displaced by the fan per revolution does notA vary much with speed so that a ian adequate for the cooling system at low operating speeds of the engine will be more than suiiicient during fast movement of the vehicle and particularly during low temperature conditions. Because of the load imposed upon the fan at high speed operation, considerable driving belt trouble has been experienced due to slippage friction and the heat resulting from such friction, and for this -reason the life of driving belts is materially shortened.

An object ,of the invention is to provide a fan which will displace a larger volume of air, per revolution, while operating at slow speeds than while operating at high speeds.

Another object of the invention is to provide a fan which will require less power for high speed rotation than for slow speed rotation.

A further object of the invention is to provide a cooling ian in which the blades automatically change form at higher operating speeds to decrease the air volume displacement so that noise is reduced and power required for operation in the higher speed range results.

Still another object of the invention is to provide a cooling fan in which the blade angle changes automatically with the speed ol' -rotation to vary the air volume displaced, per revolution, inversely with the speed of fan rotation.

Other objectsoi' the invention will appear from the following description taken in connection with the drawing, which fonns a part of this specification, and in which:

Fig. 1 is a front elevational view of an engine having my improved form of cooling fan associated therewith;

Fig. 2 is a side elevational view of the fan associated with its bearing member;

Fig. 3 is a sectional view of one of the fan blades taken on line 3 3 of Fig. 1;

Fig. 4 is a sectional view of a modied form of fan blade.

Referring now tothe drawing, I Il represents the forward end oi an internal combustion -engine adapted to be used as the power plant for driving a vehicle. Projecting from the iront end of the engine is a bearing shalt II upon which the hub I2 of a fan is mounted to rotate. At one end of the hub is fixed a grooved pulley 5 I3 with .which is associated an endless driving belt I4 driven from a moving part of the engine. Fixed to the fan hub, and preferably to the forward end thereof by means of bolts I5. is a spider I 6 from which arms Il extend radially. 10 The spider and its arms provide means for fixing the fan blades I8 to the hub I2. The arms are each formed to provide a recess into which a side edge portion oi thefan blades can be inserted, the blades being xed in such relation 15 by suitable means such as welding, as indicated at I9.

-The blades are formed of thin flexible material, preferably metal, and curve from side to side. The blades are furthermore arranged to 20 extend at an angle in the path of rotation.

As the speed of the fan increases, the pressure of air will ex or bend the blade in a direction as indicated by dotted lines at 20 inFig. 3, thereby decreasing the degree of the angle with respect to the direction of rotation. The low speed or normal angle of the fan blade is indicated at A and the angle oi' the blade at higher speed'is indicated at B in Fig. 3. It will be seen that, when the blade is in its high speed position, the angle will have decreased substantially onehali what it normally is, and thus volume of the air with which the ian blades contact during high speed rotation is considerably less than during slow speed rotation. For the same reason, there vis less resistance to be overcome by the driving belt so that slipping and frictional heat is materially reduced at high speed over what they would be if the fan blade remained at the same angle throughout the different speeds of fan rotation. The iiexible blade also permits the use of a fan to move a large volumewhen the engine is running slow, suiiicient to take care of cooling under heavy duty conditions and, at high speeds, the volume of air which is moved by such fan will be considerably reduced so that the engine is not cooled too much under low temperature conditions or when the vehicle is moving at high speed. As the blade moves to positions decreasing its curvature, a smaller area of air is contacted by the tan so that the resulting noise is reduced.

In Fig. 4, I have shown another type of blade which can be employed and, in this instance, there are two sections of thin iiexible material provide means i'or frictionally holding them t0.-A

gether at their free edge. Such means consists of a rivet 22, which extends through a transversely extending slot in the blade sections and resilient friction elements 23 which are in the form of segments of -a sphere arranged so that the shank portion of the rivet extends through openings therein. 'I'hese friction members 'engage the exterior surface of the two ian blade sections and are compressed thereagainst by their relation with the rivet. The friction means is free to move transversely of the blade during flexing at different rotational speeds and, under all operating speeds, will maintain the laminations of the bladein-Irictional relation.

V form oi laminated blade serves the' same function and operates in the same manneras the single blade shown in Fig. 3, and is another form which the invention can take. -A As shown in Figs. 3. and 4 which illustrate in dotted lines the positions of the parts when. the

fan is rotatedatfhigh speed, the relatively heavy arm of the spider'to which one side edge oi each blade is attached holds this side edge-from sub- 'stantial flexing longitudinally during the rota` under 'low speed heavy duty without producingy too great a cooling eiifect4 under high speed operation.

Although the invention has been described in connection with a specic embodiment, the principles involved are susceptible of numerous other applications which will readily occur to persons skilled in the art. The invention is therefore to be limited only as indicated by the scope of one of the arms and held substantially from exing longitudinally by said arm, said blades ex- ,tending at all points at oblique angles to the planeof hub rotation and in the same direction from said arms with respect vto the'direction of hub rotation and each flexingsimilarly side`wise throughout its length under air pressure to reduce its curvature at high 'speed operation.

length to vary their curvature inversely 'with the speed of theshait.

CLYDE R. PA'ION.y

CERTIFICATE CF CORRECTION; mem. No.: 2,052,224. February 25, 193e CLYDE R. PATCH.

, It ie hereby certifed that error appears in vChe printed specification" of that above numbered patent requiringcprrection as follows; `Page 2, secohd column, vline 1'6, claim 2, for "radal.' r'gead vertical; and that the said Letters Patent. should1 be nread with this Correction ,therein that the same may ccnfcnm 'Co` the record of the case `n -the Paten-C Offce.

. signed and' sealed This' 5thdaj of May, A. D.. 1 936.

Legna. rzer (Sealf) Acting compie-signer of gements. 

